Rain trap for prefabricated metal chimney



Feb. 4, 1969 R. L. STONE ET L RAIN TRAP FOR PREFABRICATED METAL CHIMNEY Filed on. 25, 1965 I of 2 Sheet llVl/E/VTOI? mam/w L.S7'0/V ALA/V KIN/(40 B) E ATTORNEYS Feb. 4, 1969 Elm-5mm ETAL 3,425,178

RAIN TRAP FOR PREFABRICATED METAL CHIMNEY Filed Oct. 23, 1965 Sheet of 2 v a Fig 2 nvwsn/ rare RICHARD L. STONE ALA/V KIN/(E40 By E 1 Armin/5Y5 United States Patent 1 Claim This invention relates to a rain trap for prefabricated metal chimney structures or the like.

In general, the object of the invention is to provide a means for preventing the rain that normally enters the open end of a prefabricated metal chimney from passing through it and reaching the fireplace or stove from which the chimney extends. If excessive moisture is allowed to reach the furnace or stove apparatus it can cause a serious loss of efliciency and even a malfunctioning or excessive wear and corrosion over extended periods of time. Prior to the present invention the problem was particularly severe with prefabricated metal chimneys because their naturally smooth walls allow water to flow easily toward the furnace or stove below. Previous attempts to prevent the influx of rain in chimney pipes included the use of various traps or'deflectors connected to or associated with the chimney opening or housing outside the building or above the roof level. However, these expedients were [found to have serious disadvantages. For one thing, the installation of unattractive components was architecturally undesirable. Also, such arrangements often caused a very undesirable discoloration of the roof around the chimney, or they seriously aggravated any roof leakage problem around the chimney.

Accordingly, another object of the present invention is to provide a rain trap for a prefabricated metal chimney that can be installed at various convenient locations on the chimney inside the building below the roof level. This not only avoids any roof discoloration but it also eliminates any problem of the rain trap freezing, and moreover it provides a trap that can be accessible within the house and therefore easy to clean.

A more specific object of the invention is to provide a trap device connectable in a prefabricated metal chimney that intercepts and traps rainwater which strikes the inner wall of the chimney if the rain is descending at even a small angle tothe absolute vertical. When such rain hits the inner wall'bf the chimney it rolls downwardly and is eventually trapped in an annular compartment around the chimney pipe. near its lower end. The trapped rainwater being adjacent the inner wall of the chimney is thus subjected to constant heating by the flue gases, and this causes it to evaporate at a rapid rate. Except under unusual situations, therefore, only a small amount of trapped rainwater is allowed to accumulate.

Still another object of the present invention is to provide a rain trap that can be easily coupled with existing prefabricated metal chimney sections, and which is therefore easy to install as well as having a construction that is particularly well adapted for ease and economy of manufacture.

Other objects, advantages and features of the present invention will become apparent from the following detailed description of one embodiment thereof presented in accordance with 35 U.S.C. 112.

In the drawings:

FIG. 1 is a view in elevation showing a typical chimney installation utilizing a rain trap embodying the principles of the present invention;

FIG. 2 is an enlarged plan view of the rain trap shown in FIG. 1;

3,425,178 Patented Feb. 4, 1969 FIG. 3 is a view in elevation and in section taken along the line 3-3 of FIG. 2;

FIG. 4 is a somewhat enlarged plan view of the top cap shown in FIG. 1;

FIG. 5 is a view in elevation and in section of the top cap of FIG. 4.

Referring to the drawings, FIG. 1 shows a typical prefabricated metal chimney assembly 10 having, as one of its components, a rain trap 11 embodying the principles of the present invention. Such metal chimneys are generally formed by prefabricated doublewalled sections 12, as shown, which are coupled together in vertical a1ignment by means of an end coupler. The structural details of one form of double-walled chimney now available commercially are described in Patent No. 3,170,544. The upper end of such a chimney structure usually extends well above the roof level of the building, and it may be surrounded by a suitable housing 13 which is secured to the roof. The upper end 14 of the chimney assembly 10 which may extend slightly above the chimney housing is generally open and unprotected and may therefore be fully exposed to falling rain. In somes instances, however, a top can 16 may be attached to the upper end 14, and this component and its function will be discussed in detail later with respect to FIGS. 4 and 5.

At some convenient location below the building root the rain trap device 11 is normally connected to the lower end of a starter section 17 of the chimney assembly, and above the outlet pipe 18 from a furnace, fireplace or stove designated generally by the numeral 19 and located within the building.

As discussed, the general purpose of the rain trap device 11 is to prevent any water that enters the chimney from reaching any such heat source. In the embodiment which will now be described, the size and shape of the rain trap 11 presents an outward appearance similar to that of an ordinary chimney section. As shown in FIGS. .2 and 3, it has an outer wall member 20 made of sheet metal which is spaced outwardly from a concentric inner wall member 21 made of the same material or possibly a lighter gage material. These outer and inner wall members are connected together by an annular bottom ring 22 which has an upright outer flange 23 and a downwardly extending inner flange 24. The outer flange 23 is fixed, as by spot welding or riveting, to the lower end of the outer wall member 20. The inner wall member 21 is preferably provided with an annular bead 25 which is spaced above its lower end edge 26 by a predetermined amount. This bead serves as a stop for initially retaining the inner wall 21 in an axial position relative to the outer wall 20 so that a lower end portion 27 extends below and is readily insertable into a connecting outlet pipe section 18 from the furnace or stove 19. The inner flange 24 of the annular ring 22 may also be welded, bonded or riveted to the inner wall member 21. Thus, the combination of outer and inner wall members and the lower end ring 22 form an annular fluidtight storage compartment 28 within the rain trap 11.

At the upper end of the outer wall member 20 is an annular coupling member 29 which enables the rain trap 11 to be readily connected to a prefabricated chimney section 12. This coupling member can take various forms depending 'on the coupler configuration of the chimney section to which it will be attached. In the embodiment shown, the coupling member 29 has a lower peripheral flange 30 that rests on an internal annular bead 31 located near the upper end of the outer wall member 20 and is secured thereto by welding or riveting. From the flange 30 the metal bends inwardly and upwardly to form a relatively narrow wall portion 32 and then turns inwardly to form the top portion 33 which terminates on its inner periphery by a downwardly turned flange 34. This male coupling member thus has a generally annular shape and a size which enables it to fit within a similarly shaped female coupling member 35 of a connecting chimney section 12.

At the upper end of the inner wall section 21 is an annular deflector 36 which comprises an important component of our rain trap 11. It extends upwardly and inwardly around the entire upper edge of the inner wall member 21 of the rain trap to form a surface that will catch every drop of water which flows down and drops from the inner walls of the chimney sections 12 above. In the particular construction shown, the deflector 36 has a lower flange portion 37 which is fixed to the upper edge of the inner wall member 21 and integral with an upper flange portion which forms an inwardly extending conical surface 38. The inner edge 39 of the upper deflecting flange portion has a diameter that is substantially less than the diameter of the inner peripheral flange 34 of the coupling member 29 and the diameter of all the chimney sections 12. This assures that all Water flowing downwardly from the inner walls of the chimney above will fall on and thus be deflected into the annular storage tank 28 of the rain trap 11.

In the outer wall member 20 an outlet orifice 40 is provided for draining an overflow from the rain trap in extreme conditions or for cleaning it. A hose or pipe (not shown) can be connected from this orifice to some other suitable drain facility. In actual practice the constant heat provided by the flow of gases through the chimney 10 causes the collected water to evaporate at a high rate and only during periods of particularly heavy rainfall will the water rise as high as the orifice 40.

When the chimney top is fully exposed to rainfall the percentage of rain falling into its open end which will be trapped in the rain trap 11 will depend on several factors. A most critical factor is the angle of fall of the rain. If the rain comes straight down a relatively large percentage of it will pass by the rain trap because it will not hit the inside walls of the chimney. However, rain rarely falls straight but instead falls at an angle. If the chimney has a normal height or length equivalent to one or more stories, rain falling at even a small angle (e.g., degrees from the vertical) will eventually impinge against and roll down the inside chimney walls, and all rain which hits these walls will fall onto the deflector member 36 and into the annular storage compartment 28 of my rain trap.

If it is desired to completely eliminate the possibility of any rainwater reaching the stove, fireplace or furnace beneath the chimney, the top cap 16 can be used in combination with the rain trap device 11. As shown in FIG. 4, the top cap 16 may have a disc shape with a peripheral flange 41 and a diameter that is substantially larger than the chimney opening. At least three support members 42 are evenly spaced apart and fixed at one end to the inside surface of the top cap near its periphery. At their lower ends these support members 42 are fixed to a relatively narrow circular band 43 whose ends are connected together by a tightening screw 44. The band is adaptable to fit over the end of the stub section 14 of pipe which is normally placed in the chimney opening, and is held firmly to it when the screw 44 is tightened.

With the top cap 16 and the rain trap 11 installed in combination with a prefabricated chimney 10 as shown in FIG. 1, the problem of preventing rain from reaching the heat source is completely solved because all rain that enters the chimney must impinge against its inner walls and is then trapped below. Although the rain trap thus Works with great effectiveness, it in no way reduces the efliciency of the chimney draft, and the overall result is a chimney having greater life and better operability even under the most severe weather conditions.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

We claim:

1. In a chimney assembly including a plurality of prefabricated chimney sections coupled together in vertical alignment above a heat producing means, rain protection means comprising, in combination:

a rain trap connected to and in line with a prefabricated chimney section, said rain trap being comprised of a pair of concentric Wall members;

an annular ring intetrconnecting said wall members near their lower ends and forming therewith an annular storage compartment;

an annular ring interconnecting said wall members member at its upper end and having a peripheral inner flange having a diameter substantially equal to the inside diameter of the chimney;

a deflector member fixed to the top of said inner wall member having an inwardly extending conical surface and terminating at an upper edge whose diameter is substantially less than said peripheral inner flange and the inside diameter of said chimy;

and a top cap attached to the upper end of said chimney assembly and extending completely above the area of the chimney opening and thereby preventing rain from falling vertically past said rain trap.

References Cited UNITED STATES PATENTS 1,588,321 6/1926 Lord 98-60 2,382,579 8/1945 Queirolo 126-307 2,3 92,631 1/1946 Berndt 522l8 2,482,577 9/1949 Dahlstrom 9860 3,084,479 4/1963 Struben 5216 X JOHN E. MURTAGH, Primary Examiner.

U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,425,178 February 4, 1969 Richard L. Stone et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 22, beginning with "1. In a chimney" cancel all to and including said rain trap. in line 45, same column 4 and insert:

1. In a chimney assembly including a plurality of prefabricated chimney sections coupled together in vertical alignment above a heat producing means, rain protection means comprising, in combination:

a rain trap connected to and in line with a prefabricated chimney section, said rain trap being comprised of a pair of concentric wall members;

an annular ring interconnecting said wall members near their lower ends and forming therewith an annular storage compartment;

an annular coupler member fixed to said outer wall member at its upper end and having aperipheral inner flange having a diameter substantially equal to the inside diameter of the chimney;

a deflector member fixed to the top of said inner wall member having an inwardly extending conical surface and terminating at an upper edge whose diameter is substantially less than said peripheral inner flange and the inside diameter of said chimney;

and a top cap attached to the upper end of said chimney assembled and extending completely above the area of the chimney opening and thereby preventing rain from falling vertically past said rain trap.

Signed and sealed this 17th day of March 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

1. IN A CHIMNEY ASSEMBLY INCLUDING A PLURALITY OF PREFABRICATED CHIMNEY SECTIONS COUPLED TOGETHER IN VERTICAL ALIGHMENT ABOVE A HEAT PRODUCING MEANS, RAIN PROTECTION MEANS COMPRISING, IN COMBINATION: A RAIN TRAP CONNECTED TO AND IN LINE WITH A PREFABRICATED CHIMNEY SECTION, SAID RAIN TRAP BEING COMPRISED OF A PAIR OF CONCENTRIC WALL MEMBERS; AN ANNULAR RIGN INTERCONNECTING SAID WALL MEMBERS NEAR THEIR LOWER ENDS AND FORMING THEREWITH AN ANNULAR STORAGE COMPARTMENT; AN ANNULAR RING INTERCONNECTING SAID WALL MEMBERS MEMBER AT ITS UPPER END AND HAVING A PERIPHERAL INNER FLANGE HAVING A DIAMETER SUBSTANTIALLY EQUAL TO THE INSIDE DIAMETER OF THE CHIMNEY; A DEFLECTOR MEMBER FIXED TO THE TOP OF SAID INNER WALL MEMBER HAVING AN INWARDLY EXTENDING CONICAL SURFACE AND TERMINATING AT AN UPPER EDGE WHOSE DIAMETER IS SUBSTANTIALLY LESS THAN SAID PERIPHERAL INNER FLANGE AND THE INSIDE DIAMETER OF SAID CHIMNEY; AND A TOP CAP ATTACHED TO THE UPPER END OF SAID CHIMNEY ASSEMBLY AND EXTENDING COMPLETELY ABOVE THE AREA OF THE CHIMNEY OPENING AND THEREBY PREVENTING RAIN FROM FALLING VERTICALLY PAST SAID RAIN TRAP. 